Nowadays, “implant treatments” are universally prevalent. Implant treatments designate procedures for repairing tooth loss due to aging, periodontal diseases, or the like, by implanting an artificial tooth root into an alveolar bone, and covering the implanted tooth root with an artificial crown and an superstructure.
When a tooth is lost, (i.e., when a tooth comes out), the alveolar bone that has supported the tooth is immediately absorbed and reduced. Therefore, during implant treatments, alveolar bone is often found to be of insufficient thickness for the implantation of artificial tooth root. The insufficient thickness of the alveolar bone will likely make the implanted artificial tooth root unstable. Therefore, when the alveolar bone has an insufficient thickness, bone grafting or bone regeneration is conducted.
The GBR (guided bone regeneration) method is one of the common techniques for alveolar bone regeneration. In the GBR method, pulverized autogenous bone or a bone prosthetic material is placed in the part (affected part) where the alveolar bone is reduced, and a membrane (also called a shield membrane or a GBR membrane) is placed thereon (i.e., the affected part filled with the bone prosthetic material is covered with the membrane. In this manner, the GBR method promotes regeneration of alveolar bone while preventing entry of the gingival tissue. However, the existing bone prosthetic materials are insufficient in cell attachment and cell proliferation. For this reason, alveolar bone regeneration takes a long time. Moreover, since the existing bone prosthetic materials have insufficient adhesiveness to alveolar bones and insufficient retention in the affected part, leakage of the material often occurs even after the material is covered with the GBR membrane.
Further, although implant treatments occasionally use bone cement, bone cement has a drawback in that it blocks cell infiltration.
As described above, currently available bone regeneration materials suffer from insufficient cell attachment and cell proliferation.
In order to solve such drawbacks, study and development was continued to invent a bone regeneration material suitable for bone (in particular, alveolar bone) regeneration (e.g., see Patent Documents 1 and 2).